Ring-opening processes and catalysts for hydrocarbon species comprising aromatic and cycloparaffinic rings

ABSTRACT

Embodiments of the disclosure include processes for ring-opening of hydrocarbon species comprising aromatic and cycloparaffinic rings in hydrocarbon feeds to produce ring-opened products. In particular, the process comprises contacting hydrocarbon species comprising aromatic and cycloparaffinic rings with hydrogen in the presence of a ring-opening catalyst comprising a noble metal on a low-acidity crystalline material containing external pockets to facilitate ring-opening of the hydrocarbon species comprising aromatic and cycloparaffinic rings. The processes are useful in the transformation of polynuclear aromatic hydrocarbons (PAHs) to ring-opened products.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 63/167,293 filed Mar. 29, 2021, the entire contents ofwhich are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to processes for converting hydrocarbonspecies comprising aromatic and cycloparaffinic rings in hydrocarbonfeeds with metal catalysts on low-acidity, crystalline materials.

BACKGROUND

Hydrocracking processes are routinely used in refining to transformmixtures of hydrocarbons into products which can be upgraded easily. Inorder to increase the conversion of hydrocracking units, a portion ofthe unconverted feed is recycled, either to the reaction section throughwhich it has already passed, or to an independent reaction section.Polynuclear aromatic hydrocarbons (PAHs) formed during crackingreactions accumulate in recycle streams of hydrocracking units. Thesespecies cause plugging of equipment and poison hydroprocessingcatalysts.

PAHs comprise several condensed benzene nuclei or rings. Heavypolynuclear aromatic hydrocarbons, which include at least 3 benzenerings in each molecule, can be more difficult to hydrogenate and morelikely to poison the catalysts. PAHs are solid materials with lowvolatility and low degradation rate. As such, PAHs tend to prevail overextended periods of time, for example in creosote and asphalt. Hundredsof types of PAH compounds have been identified in these materials.

Under certain hydrogenation conditions, PAHs can be treated to formpartially hydrogenated hydrocarbon species which contain aromatic andcycloparaffinic rings.

In hydrocracking processes, it is desirable to open the rings ofcycloparaffins to produce n-paraffins and branched paraffins. Inparticular, cycloparaffin-ring opening is an important reaction forupgrading petroleum streams to lubricant base stocks.

There remains a need for a process for converting PAHs and PAHprecursors (e.g. partially hydrogenated polynuclear hydrocarbons) tolighter species, thereby reducing processing problems and facilitatingthe conversion of PAHs to valuable products.

In view of the foregoing, there is an ongoing need to providecycloparaffin ring-opening catalysts and processes for improvinghydroconversion of cycloparaffins in hydrocarbon feeds.

SUMMARY

This summary is provided to introduce various concepts in a simplifiedform that are further described below in the detailed description. Thissummary is not intended to identify required or essential features ofthe claimed subject matter nor is the summary intended to limit thescope of the claimed subject matter.

Aspects of this disclosure are directed to processes for selectivering-opening of aromatic and cycloparaffinic rings in hydrocarbon feedsto produce ring-opened products. Advantageously, the processes can beused to selectively produce ring-opening of cycloparaffin rings and canbe used to convert polynuclear aromatic hydrocarbons (PAHs) to lighterspecies.

In one aspect, a process for selective ring-opening of aromatic andcycloparaffinic rings comprises: contacting hydrocarbon speciescomprising aromatic and cycloparaffinic rings with hydrogen in thepresence of a ring-opening catalyst comprising a noble metal on alow-acidity crystalline material containing external pockets tofacilitate ring-opening of the hydrocarbon species comprising aromaticand cycloparaffinic rings.

In another aspect, a process for converting polynuclear aromatichydrocarbons (PAHs) to ring-opened products comprises: (i) hydrogenationof PAHs by a hydrogenation catalyst and hydrogen to produce hydrocarbonspecies comprising aromatic and cycloparaffinic rings (i.e., partiallyhydrogenated species comprising aromatic and cycloparaffinic rings); and(ii) contacting the hydrocarbon species comprising aromatic andcycloparaffinic rings with hydrogen in the presence of a ring-openingcatalyst comprising a noble metal on a low-acidity crystalline materialcontaining external pockets to facilitate ring-opening of thehydrocarbon species comprising aromatic and cycloparaffinic rings.

In another aspect, hydrogen and a ring-opening catalyst comprising anoble metal on a low-acidity crystalline material containing externalpockets are used to facilitate ring-opening of hydrocarbon speciescomprising aromatic and cycloparaffinic rings in accordance with aprocess described herein.

In another aspect, a composition comprises a ring-opened hydrocarbonspecies produced from hydrocarbon species comprising aromatic andcycloparaffinic rings treated in accordance with a process describedherein.

This summary and the following detailed description provide examples andare explanatory only of the disclosure. Accordingly, the foregoingsummary and the following detailed description should not be consideredto be restrictive. Additional features or variations thereof can beprovided in addition to those set forth herein, such as for example,various feature combinations and sub-combinations of those described inthe detailed description.

DEFINITIONS

To define more clearly the terms used herein, the following definitionsare provided. Unless otherwise indicated, the following definitions areapplicable to this disclosure. If a term is used in this disclosure butis not specifically defined herein, the definition from the IUPACCompendium of Chemical Terminology can be applied, as long as thatdefinition does not conflict with any other disclosure or definitionapplied herein or render indefinite or non-enabled any claim to whichthat definition is applied. To the extent that any definition or usageprovided by any document incorporated herein by reference conflicts withthe definition or usage provided herein, the definition or usageprovided herein controls.

While compositions and methods are described in terms of “comprising”various components or steps, the compositions and methods can also“consist essentially of” or “consist of” the various components orsteps, unless stated otherwise.

The terms “a,” “an,” and “the” are intended to include pluralalternatives, e.g., at least one. The terms “including”, “with”, and“having”, as used herein, are defined as comprising (i.e., openlanguage), unless specified otherwise.

Various numerical ranges are disclosed herein. When Applicant disclosesor claims a range of any type, Applicant's intent is to disclose orclaim individually each possible number that such a range couldreasonably encompass, including end points of the range as well as anysub-ranges and combinations of sub-ranges encompassed therein, unlessotherwise specified. For example, all numerical end points of rangesdisclosed herein are approximate, unless excluded by proviso.

Values or ranges may be expressed herein as “about”, from “about” oneparticular value, and/or to “about” another particular value. When suchvalues or ranges are expressed, other embodiments disclosed include thespecific value recited, from the one particular value, and/or to theother particular value. Similarly, when values are expressed asapproximations, by use of the antecedent “about,” it will be understoodthat the particular value forms another embodiment. It will be furtherunderstood that there are a number of values disclosed therein, and thateach value is also herein disclosed as “about” that particular value inaddition to the value itself. In another aspect, use of the term “about”means±20% of the stated value, ±15% of the stated value, ±10% of thestated value, ±5% of the stated value, ±3% of the stated value, or ±1%of the stated value.

“Periodic Table” refers to the version of IUPAC Periodic Table of theElements dated Jun. 22, 2007, and the numbering scheme for the PeriodicTable Groups is as described in Chemical and Engineering News, 63(5), 27(1985).

“Hydrocarbonaceous” and “hydrocarbon” refer to a compound containingonly carbon and hydrogen atoms. Other identifiers may be used toindicate the presence of particular groups, if any, in the hydrocarbon(e.g., halogenated hydrocarbon indicates the presence of one or morehalogen atoms replacing an equivalent number of hydrogen atoms in thehydrocarbon).

“Hydroprocessing” or “hydroconversion” refers to a process in which acarbonaceous feedstock is brought into contact with hydrogen and acatalyst, at a higher temperature and pressure, for the purpose ofremoving undesirable impurities and/or converting the feedstock to adesired product. Such processes include, but are not limited to,methanation, water gas shift reactions, hydrogenation, hydrotreating,hydrodesulphurization, hydrodenitrogenation, hydrodemetallation,hydrodearomatization, hydroisomerization, hydrodewaxing andhydrocracking including selective hydrocracking. Depending on the typeof hydroprocessing and the reaction conditions, the products ofhydroprocessing can show improved physical properties such as improvedviscosities, viscosity indices, saturates content, low temperatureproperties, volatilities and depolarization.

“Hydrocracking” refers to a process in which hydrogenation anddehydrogenation accompanies the cracking/fragmentation of hydrocarbons,e.g., converting heavier hydrocarbons into lighter hydrocarbons, orconverting aromatics and cycloparaffins into non-cyclic paraffins.

“Cycloparaffin” refers to a compound having the general formulaC_(n)H_(2n) and is characterized by having one or more rings ofsaturated carbon atoms. In cycloparaffins with multiple rings, the ringscan be fused. Cycloparaffins can include substituents and aromaticrings, but must also contain one or more rings of saturated carbonatoms.

The terms “binder” or “support”, particularly as used in the term“catalyst support”, refer to conventional materials that are typically asolid with a high surface area, to which catalyst materials are affixed.Support materials may be inert or participate in the catalyticreactions, and may be porous or non-porous. Typical catalyst supportsinclude various kinds of carbon, alumina, silica, and silica-alumina,e.g., amorphous silica aluminates, zeolites, alumina-boria,silica-alumina-magnesia, silica-alumina-titania and materials obtainedby adding other zeolites and other complex oxides thereto.

“Molecular sieve” refers to a crystalline microporous solid havinguniform pores of molecular dimensions within a framework structure, suchthat only certain molecules, depending on the type of molecular sieve,have access to the pore structure of the molecular sieve, while othermolecules are excluded, e.g., due to molecular size and/or reactivity.Zeolites, crystalline aluminophosphates and crystallinesilicoaluminophosphates are representative examples of molecular sieves.

The terms “catalyst particles”, “catalyst composition,” “catalystmixture,” “catalyst system,” and the like, encompass the initialstarting components of the composition, as well as whatever product(s)may result from contacting these initial starting components, and thisis inclusive of both heterogeneous and homogenous catalyst systems orcompositions.

Applicant reserves the right to proviso out or exclude any individualmembers of any such group of values or ranges, including any sub-rangesor combinations of sub-ranges within the group, that can be claimedaccording to a range or in any similar manner, if for any reasonApplicant chooses to claim less than the full measure of the disclosure,for example, to account for a reference that Applicant may be unaware ofat the time of the filing of the application. Further, Applicantreserves the right to proviso out or exclude any members of a claimedgroup.

Although any processes and materials similar or equivalent to thosedescribed herein can be used in the practice or testing of theinvention, the typical processes and materials are herein described.

All publications and patents mentioned herein are incorporated herein byreference for the purpose of describing and disclosing, for example, theconstructs and methodologies that are described in the publications,which might be used in connection with the presently describedinvention. The publications discussed throughout the text are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that theinventors are not entitled to antedate such disclosure by virtue ofprior invention.

DETAILED DESCRIPTION

It is to be understood that the disclosure is not limited in itsapplication to the details of construction and the arrangement ofcomponents set forth in the following description or illustrated in thedrawings.

The present disclosure generally relates to processes for convertingpolynuclear aromatic hydrocarbons (PAHs) and PAH precursors (e.g.partially hydrogenated polynuclear hydrocarbons or hydrocarbon speciescomprising aromatic and cycloparaffinic rings) to ring-opened products,thereby reducing processing problems and faciliatating the conversion ofPAHs to valuable products. In particular, the present disclosure relatesto exemplary ring-opening catalysts, which facilitate ring-opening ofhydrocarbon species comprising aromatic and cycloparaffinic ringspresent in any hydrocarbon feed, such as a hydrocracker recycle stream.The processes according to the embodiments comprise at least the step ofcontacting the hydrocarbon species comprising aromatic andcycloparaffinic rings with hydrogen in the presence of a ring-openingcatalyst comprising a noble metal on a low-acidity crystalline materialcontaining external pockets to facilitate ring-opening of thehydrocarbon species comprising aromatic and cycloparaffinic rings.Exemplary ring-opening catalysts include, for example, one or more noblemetals on a low-acidity crystalline material formed from thedelamination of a zeolite selected from a borosilicate oraluminoborosilicate molecular sieve containing at least 0.05 weightpercent boron and less than 1000 ppm by weight of aluminum, or atitanosilicate molecular sieve; aluminosilicate; and silico-aluminiumphosphates and mixtures thereof. In particular embodiments, thelow-acidity crystalline material can be formed from the delamination ofone or more types of zeolite selected from: SSZ-33, SSZ-46, SSZ-53,SSZ-55, SSZ-57, SSZ-58, SSZ-59, SSZ-60, SSZ-64, SSZ-70, ZSM-5, ZSM-11,TS-1, MTT (e.g., SSZ-32, ZSM-23 and the like), H—Y and combinationsthereof.

In particular embodiments, the low-acidity crystalline material can beformed from the delamination of one or more types of zeolite selectedfrom: SSZ-35, SSZ-54, SSZ-70, SSZ-74, SSZ-91, SSZ-95, SSZ-109, SSZ-31,SSZ-42, SSZ-43, SSZ-48, SSZ-55, SSZ-57, SSZ-63, SSZ-64, SSZ-65, SSZ-96,SSZ-106, Y, USY, Beta, ZSM-4, MFI (e.g., ZSM-5), ZSM-12, ZSM-18, ZSM-20,MTT (e.g., ZSM-23), FER (e.g., ZSM-35), *MRE (e.g., ZSM-48), L andcombinations thereof.

Generally, the processes are applied to a hydrocarbon feed (for example,a hydrocracker recycle stream) which comprises aromatic andcycloparaffinic rings. In certain embodiments, the processes comprisethe step of contacting the hydrocarbon species comprising aromatic andcycloparaffinic rings with hydrogen in the presence of a ring-openingcatalyst comprising a noble metal on a low-acidity crystalline materialcontaining external pockets to facilitate ring-opening of thehydrocarbon species comprising aromatic and cycloparaffinic rings.

In certain embodiments, the process comprises the steps of (i)hydrogenation of PAHs by a hydrogenation catalyst and hydrogen to toproduce hydrocarbon species comprising aromatic and cycloparaffinicrings (i.e., partially hydrogenated species comprising aromatic andcycloparaffinic rings); (ii) contacting the hydrocarbon speciescomprising aromatic and cycloparaffinic rings with hydrogen in thepresence of a ring-opening catalyst comprising a noble metal on alow-acidity crystalline material containing external pockets tofacilitate ring-opening of the hydrocarbon species comprising aromaticand cycloparaffinic rings.

Hydrogenation of PAHs

A polynuclear (or polycyclic) aromatic hydrocarbon (PAH) is ahydrocarbon comprising two or more aromatic rings, for example C₁₀ toC₃₂ PAHs. PAHs are uncharged, non-polar molecules, with distinctiveproperties due in part to the delocalized electrons in their aromaticrings. Heavier PAHs comprise at least 4, or at least 6, benzene rings ineach molecule.

Polynuclear aromatic hydrocarbons are primarily found in natural sourcessuch as bitumen. PAHs can also be produced geologically when organicsediments are chemically transformed into fossil fuels such as oil andcoal. The rare minerals idrialite, curtisite, and carpathite consistalmost entirely of PAHs that originated from such sediments. Examples ofPAHs are shown in Table 1.

TABLE 1 Example polynuclear aromatic hydrocarbons Name StructureNaphthalene

Pyrene

Biphenyl

Pentacene

Fluorene

Perylene

Anthracene

Benzo[a]pyrene

Phenanthrene

Corannulene

Phenalene

Benzo[ghi]perylene

Tetracene

Coronene

Chrysene

Ovalene

Triphenylene

Benzo[c]fluorene

In processes according to the embodiments, the hydrogenation of PAHsoccurs by contacting the PAHs, or a hydrocarbon feed comprising PAHs,with a hydrogenation catalyst and hydrogen to produce partiallyhydrogenated species comprising aromatic and cycloparaffinic rings(i.e., hydrocarbon species comprising aromatic and cycloparaffinicrings). A wide variety of feeds may be treated in the hydrogenationstep. The boiling point of the compounds in the feed are notparticularly limited. In certain embodiments, the feed comprises atleast 10% by volume, at least 20% by volume, or least 80% by volume ofcompounds boiling above 340° C.

Generally, the feed may be any feed in which the major componentconsists of hydrocarbons and the feed has a low nitrogen and low sulfurcontent. In certain embodiments, the feed has about 50 ppm or lessnitrogen. In certain embodiments, the feed has about 50 ppm or lesssulfur. The feed may, for example, be hydrocracker recycle streams,light gas oils obtained from a catalytic cracking unit), as well asfeeds originating from units for the extraction of aromatics fromlubricating oil bases or obtained from solvent dewaxing of lubricatingbase oils, or the feed may in fact be a deasphalted oil, effluents froma Fischer-Tropsch unit or in fact any mixture of the feeds cited above.The above list is not limiting.

In general, the feeds have a T5 boiling point of more than 150° C. (i.e.95% of the compounds present in the feed have a boiling point of morethan 150° C.). In the case of gas oil, the T5 point is generallyapproximately 150° C. In the case of VGO, the T5 is generally more than340° C., or even more than 370° C. The feeds which may be used thus fallwithin a wide range of boiling points. This range generally extends fromgas oil to VGO, encompassing all possible mixtures with other feeds, forexample LCO.

The hydrogenation catalyst and conditions for the hydrogenation step canbe any suitable hydrogenation catalyst and conditions known in the art.In certain embodiments, the hydrogenation catalyst is a highly activehydrogenation catalyst comprising a metal selected from the groupconsisting of platinum, palladium, nickel, ruthenium, rhodium, osmium,iridium, and gold, for example platinum, on a support such as alumina orsilica.

In the hydrogenation step, two or more hydrogens are added to the PAHstructure, HnPAH is formed, wherein n is an even integer of 2 or more.Generally, the PAH compound is not completely hydrogenated, but theHnPAH compounds may include partially or completely hydrogenatedcompounds. The HnPAH products include hydrocarbon species comprisingaromatic and cycloparaffinic rings. An example of phenanthrene andhydrogenation products thereof is shown in Scheme 1 below.

Cycloparaffinic rings are residues of cycloparaffins, which arecompounds having the general formula C_(n)H_(2n) and one or more ringsof saturated carbon atoms. In cycloparaffins with multiple rings, therings can be fused. Cycloparaffins can include substituents and aromaticrings, but must also contain one or more rings of saturated carbonatoms.

Catalyzed Ring-Opening of Hydrocarbon Species Comprising Aromatic andCycloparaffinic Rings

In processes according to the embodiments, the catalyzed ring-opening ofthe PAHs-hydrogenation products or the hydrocarbon species comprisingaromatic and cycloparaffinic rings occurs by contacting the hydrocarbonspecies comprising aromatic and cycloparaffinic rings with hydrogen inthe presence of a ring-opening catalyst comprising a noble metal on alow-acidity crystalline material containing external pockets tofacilitate ring-opening of the hydrocarbon species comprising aromaticand cycloparaffinic rings.

In certain embodiments, the process comprises cycloparaffinicring-opening by contacting a cycloparaffin with hydrogen in the presenceof a ring-opening catalyst comprising a noble metal on a low-aciditycrystalline material. In general, the ring-opening catalyst comprises anoble metal-containing, low-acidity, crystalline material with externalpockets which facilitates ring-opening (i.e., carbon-carbon bondbreaking) between unsubstituted carbon atoms in a cycloalkyl portion inthe cycloparaffinic rings of the PAHs-hydrogenation products or thehydrocarbon species comprising aromatic and cycloparaffinic rings.

In certain embodiments, the processes disclosed herein may be used forreacting a feed comprising hydrocarbon species comprising aromatic andcycloparaffinic rings at conditions of elevated temperatures andpressures in the presence of hydrogen and ring-opening catalystparticles to open the cycloparaffinic rings in the feed, i.e. to convertthe cycloparaffinic rings to branched paraffin moieties.

Cycloparaffin ring-opening is an important reaction for upgradingpetroleum streams. Superior cold flow properties (i.e., low pour point)can be achieved by converting cycloparaffins to branched paraffins.Aromatic ring saturation may also occur during the processes describedherein. In certain embodiments, the processes can be used to upgradecomponents containing aromatic rings to branched paraffins or branchedcycloparaffins, thereby improving viscosity index cold flow properties.

Exemplary ring-opening catalysts include, for example, one or moremetals on a low-acidity crystalline material formed from thedelamination of a zeolite selected from a borosilicate oraluminoborosilicate molecular sieve containing at least 0.05 weightpercent boron and less than 1000 ppm by weight of aluminum, or atitanosilicate molecular sieve; aluminosilicate; and silico-aluminiumphosphates and mixtures thereof. In particular embodiments, thelow-acidity crystalline material can be formed from the delamination ofone or more types of zeolite selected from: SSZ-33, SSZ-46, SSZ-53,SSZ-55, SSZ-57, SSZ-58, SSZ-59, SSZ-60, SSZ-64, SSZ-70, ZSM-5, ZSM-11,TS-1, MTT (e.g., SSZ-32, ZSM-23 and the like), H—Y and combinationsthereof.

In particular embodiments, the low-acidity crystalline material can beformed from the delamination of one or more types of zeolite selectedfrom: SSZ-35, SSZ-54, SSZ-70, SSZ-74, SSZ-91, SSZ-95, SSZ-109, SSZ-31,SSZ-42, SSZ-43, SSZ-48, SSZ-55, SSZ-57, SSZ-63, SSZ-64, SSZ-65, SSZ-96,SSZ-106, Y, USY, Beta, ZSM-4, MFI (e.g., ZSM-5), ZSM-12, ZSM-18, ZSM-20,MTT (e.g., ZSM-23), FER (e.g., ZSM-35), *MRE (e.g., ZSM-48), L andcombinations thereof.

In certain embodiments, the ring-opening catalyst comprises a noblemetal selected from the group consisting of platinum, palladium, nickel,rhodium, iridium, ruthernium, osmium and mixtures thereof. In certainembodiments, the noble metal is selected from the group consisting ofplatinum, nickel, rhodium and mixtures thereof. In certain embodiments,the noble metal comprises platinum.

The metal may be incorporated into the catalyst composition by anysuitable method known in the art, such as impregnation or exchange ontothe zeolite. The metal may be incorporated in the form of a cationic,anionic or neutral complex. For example, [Pt(NH₃)_(4]) ²+ and cationiccomplexes of this type will be found convenient for exchanging platinumonto the zeolite. In certain embodiments, the amount of metal on thezeolite is about 0.003 to about 10 percent by weight, about 0.01 toabout 10 percent by weight, about 0.1 to about 2.0 percent by weight, orabout 0.1 to about 1.0 percent by weight. In certain embodiments, theamount of platinum on the zeolite is about 0.01 to about 10 percent byweight, about 0.1 to about 2.0 percent by weight, or about 0.1 to about1.0 percent by weight. In certain embodiments, the source of platinum inthe catalyst synthesis is platinum tetraamine dinitrate. In certainembodiments, the metal is introduced into the catalyst composition witha pH neutral or basic solution. In certain embodiments, the platinum isintroduced into the catalyst composition with a pH neutral or basicsolution.

A high level of metal dispersion in the catalyst or catalyst compositionis generally preferred. For example, platinum dispersion is measured bythe hydrogen chemisorption technique and is expressed in terms of H/Ptratio. The higher the H/Pt ratio, the higher the platinum dispersion. Incertain embodiments, the zeolite should have an H/Pt ratio greater thanabout 0.8.

One or more binder materials may also be used with the zeolite.Generally desirable properties for the binder material are goodmixing/extrusion characteristics, good mechanical strength aftercalcination, and reasonable surface area and porosity to avoid possiblediffusion problems during catalyst use. Examples of suitable bindermaterials include, but are not limited to: silica-containing bindermaterials, such as silica, silica alumina, silica-boria,silica-magnesia, silica-zirconia, silica-thoria, silica-berylia,silica-titania, silica-alumina-boria, silica alumina-thoria,silica-alumina-zirconia, silica-alumina magnesia orsilica-magnesia-zirconia; inorganic oxides; aluminum phosphate; andcombinations thereof. In certain embodiments, the binder material doesnot comprise zeolitic materials.

When used, the ratio of binder to zeolite will typically vary from about9:1 to about 1:9, more commonly from about 3:1 to about 1:3 (by weight).

Generally, the zeolite useful in the catalyst compositions and processesdescribed herein is an aluminosilicate with low-acidity, including lowalumina content and a high silica-to-alumina mole ratio. In oneembodiment, the zeolite is an aluminosilicate. In certain embodiments,the zeolite is an aluminosilicate having a low alumina content and ahigh silica-to-alumina mole ratio.

Typically, the process is conducted under suitable hydrocrackingconditions for the particular catalyst used. In certain embodiments, theprocess is conducted at a temperature of about 200° C. to about 400° C.In certain embodiments, the process is conducted at a pressure in therange of about 1 psig to about 2500 psig. In certain embodiments, theprocess is conducted at a weight hourly space velocity in the range ofabout 0.4 to about 2.0 WHSV hr⁻¹.

The amount of hydrogen present in the process can be in the range ofabout 2 to about 10 for the H₂/cycloparaffin mole ratio. Typically, theamount of hydrogen present in the process is in the range of about 3 toabout 5 for the H₂/cycloparaffin mole ratio.

In one embodiment, a hydrotreating step using a conventionalhydrotreating catalyst may also be carried out to remove nitrogen andsulfur and to saturate aromatics to naphthenes without substantialboiling range conversion. Suitable hydrotreating catalysts generallycomprise a metal hydrogenation component, usually a Group 6 or Group8-10 metal. Hydrotreating will usually improve catalyst performance andpermit lower temperatures, higher space velocities, lower pressures orcombinations of these conditions to be employed.

The process of the present disclosure provides a number of advantages,as supported by the examples that follow, including facilitatingring-opening of cycloparaffins between unsubstituted carbons with highconversion rates and high selectivity. In certain embodiments, theprocess results in greater than about 90% conversion of thecycloparaffins in the hydrocarbon feed. In certain embodiments, theprocess results in selectivity for ring-opening products of greater thanabout 60% or about 65% of the cycloparaffins in the hydrocarbon feed.Advantageously, processes according to the embodiments can be used tofacilitate cycloparaffin ring-opening without excessive formation ofless-valuable light products (e.g., gases such as methane, ethane andpropane).

Methods of Preparing the Low-acidity Crystalline Materials and Catalysts

The ring-opening catalysts according to the embodiments include one ormore noble metals on a low-acidity crystalline material formed from thedelamination of suitable zeolites. The low-acidity crystalline materialcomprises external pockets which are formed by the delamination of thezeolites. Suitable zeolites contain large cavities which, upondelamination, become large exterior pockets. These pockets areadvantageous in the adsorption of polynuclear aromatic hydrocarbons. Thelow-acidity crystalline materials also have high external surface areas,allowing for a large concentration of catalytic sites and thus allowingreactions to proceed at rates that are well-suited for industrialapplications.

Zeolite catalysts are widely used in petroleum refining and finechemical synthesis. The well-defined active sites of zeolites, whichconsist of heteroatoms substituted within framework positions, impactthe utility and shape selectivity of these materials in catalyticreactions. Many small molecule substrates readily fit inside themicropore of zeolites, where most active sites are located. In theinterest of expanding the scope of substrates to include largermolecules, zeolite-based materials such as extra-large-pore zeolites,delaminated layered zeolite precursor materials, single-unit-cellzeolite nanosheets, hierarchically nanoporous zeolite-like materials,and self-pillared zeolite nanosheets have been developed. Thesematerials facilitate catalytic reactions with sterically bulkysubstrates (or reactants), which would be unable to access active siteswithin internal micropores.

Ouyang et al. report a delaminated borosilicate zeolite precursormaterial displays a 2.3-fold enhancement in its initial rate ofcatalysis relative to the 3D-calcined material, which is nearly equal toits 2.5-fold measured increase in external surface area (see X. Ouyanget al., J. Am. Chem. Soc. 2014, 136, 1449-1461.) A layered borosilicatezeolite precursor ERB-1P (SUB=11) was delaminated via isomorphoussubstitution of aluminum for boron using aqueous aluminum nitratetreatment to produce the delaminated zeolite catalyst.

U.S. Pat. No. 9,795,951 describes certain surfactant-free, single-stepsyntheses of delaminated aluminosilicate zeolites.

In certain embodiments, the low-acidity crystalline material can beformed from the delamination of one or more types of zeolite describedherein. Delamination refers to the peeling apart of layers in a zeolite.Through the delamination process, the low-acidity crystalline materialaccording to the embodiments is formed. Delamination is oftenaccompanied by an increase in the external surface area of the material,sometimes by as much as 10 fold. Preferably, the delamination stepfacilitates an increase in surface area that is largely due to theincrease in external surface area exposed rather than contributions fromother phases such as amorphous phases.

The low-acidity crystalline materials may comprise delaminatedmetallosilicate zeolites, such as those described in U.S. Pat. No.9,795,951, the entirety of which is incorporated herein by reference.For example, the low-acidity crystalline materials may be prepared by aprocess comprising exfoliating zeolites (e.g., borosilicate zeolite) viadisruption of hydrogen bonds between layers by treating with warm metalsalt solutions. In such delamination (exfoliation) processes, the metalsalt solution can be either a dissolved metal salt in a solvent or theneat metal salt, in the case of metal salts that are themselvesintrinsically liquids under conditions of contacting. The metal saltrefers to any coordination of a metal cation with an anion includinginorganic anions such as nitrate and chloride as well as organic anionssuch as acetate and citrate and organic ligands such as alkoxide,carboxylates, halides and alkyls.

In certain embodiments, the exfoliation of the zeolites comprisestreatment of the zeolites in warm ARNO), aqueous solution. During thistreatment, interlayer hydrogen bonding in the zeolite is disrupted (andpersists even after calcination at 550° C.) via lattice distortion,which is induced by substitution of B for Al.

In certain embodiments, the exfoliation of the zeolites comprisestreatment of the zeolites in warm Zn(NO₃)₂ aqueous solution at pH ofabout 1. The interlayer hydrogen bonding in the zeolite is disrupted,and accompanied by the formation of silanol nests induced by B removalfrom the framework. Within this context, silanol nests refers to aplurality of silanols arranged within a template that used to beoccupied by B. The high surface area and silanol nests of the exfoliatedzeolites persist even after calcination at 550° C.

In certain embodiments, after delamination, the crystalline material maybe partially demetallated, for example, to afford a more activecatalyst. Partial demetallation refers to removal of a portion of theheteroatoms within the catalyst, typically the portion that is bondedmore weakly and, typically, this is the portion that is not as fullycondensed to the zeolite framework. When applied to Al metal, theprocess of demetallation is termed dealumination. There are severalpreferred methods of dealumination, and this specification is not to belimited in any way based on the method of demetallation practiced. Forexample, it is well known in the art that dealumination can accomplishedby either (i) a brief aqueous acid solution treatment (Barrer, R. M.,Makki, M. B. (1964) Can J Chem 42:1481); (ii) steam treatment (Scherzer,J. The Preparation and Characterization of Aluminum Deficient Zeolite,“Catalytic Materials” ACS Symposium Series. 1984, 248:157-200); and(iii) ammonium fluorosilicate treatment (Breck, D. W., Blass, H.,Skeels, G. W. (1985) U.S. Pat. No. 4,503,023, Union Carbide Corp).

In certain embodiments, the low-acidity crystalline material is adelaminated aluminosilicate zeolite. In certain embodiments, thelow-acidity crystalline material is formed from the delamination of oneor more types of aluminosilicate zeolite. Once recovered from metal saltsolution, the delaminated aluminosilicate zeolite can be calcined.

In certain embodiments, the low-acidity crystalline materials comprisedisordered stacking of thin sheets along the c-axis. Generally, thelow-acidity crystalline materials possess a high density of strong acidsites on the external surface.

In certain embodiments, the low-acidity crystalline materials comprise adelaminated silanol-nest-containing zeolite.

The low-acidity crystalline materials may comprise delaminated zeolites,such as those described in U.S. Patent Publication No. 2012/0148487, theentirety of which is incorporated herein by reference. For example, thelow-acidity crystalline materials may be prepared by a processcomprising exfoliating zeolites comprising preparing a non-aqueousmixture of chloride and fluoride anions comprising an organic solventand a zeolite to be delaminated, maintaining the mixture at atemperature in the range of about 50 to about 150° C. for a length oftime sufficient to effect the desired delamination, then recovering thelow-acidity crystalline materials. The organic solvent can be anysuitable organic solvent, such as dimethyl formamide. Generally,acidification is used to recover the product.

In certain embodiments, the low-acidity crystalline material can beformed from the delamination of one or more types of zeolite selectedfrom MCM-22 (P), SSZ-25, ERB-1, PREFER, SSZ-70 (e.g., Al-SSZ-70, orB-SSZ-70) and Nu-6(1). The chloride and fluoride anions can be obtainedfrom any source of the anions. The molar ratio of chloride to fluorideanions can be in the range of about 100:1 to 1:100. Any compound whichwill provide the anions in aqueous solution can be used. Any suitablecation can be used in the delamination process. In certain embodiments,the cation comprises an alkylammonium cation, wherein the alkyl group isa C₁ to C₂₀ alkyl group.

In one aspect, the present disclosure provides for using hydrogen and aring-opening catalyst comprising a noble metal on a low-aciditycrystalline material containing external pockets to facilitatering-opening of hydrocarbon species comprising aromatic andcycloparaffinic rings in a process according to the embodimentsdescribed herein.

In another aspect, the present disclosure provides for a compositioncomprising a ring-opened hydrocarbon species produced from hydrocarbonspecies comprising aromatic and cycloparaffinic rings treated in aprocess according to the embodiments described herein.

EXAMPLES

The disclosed embodiments are further illustrated by the followingexamples, which are not to be construed in any way as imposinglimitations to the scope of this disclosure. Various other aspects,embodiments, modifications, and equivalents thereof may be apparent toone of ordinary skill in the art, after reading the description herein,without departing from the scope of the present disclosure or the scopeof the amended claims.

Example 1

An alumina carrier material comprising 1/16 inch spheres is prepared by:forming an aluminum hydroxyl chloride sol by dissolving substantiallypure aluminum pellets in a hydrochloric acid solution, addinghexamethylenetetramine to the resulting alumina sol, gelling theresulting solution by dropping it into an oil bath to form sphericalparticles of an alumina hydrogel, aging and washing the resultingparticles and finally drying and calcining the aged and washed particlesto form spherical particles of gamma-alumina containing about 0.3 wt %combined chloride.

Measured amounts of the desired noble metal compounds, for examplechoroplatinic acid, are dissolved in a suitable solvent, for examplewater, with a strong acid such as hydrogen chloride to form animpregnation solution. If more than one metal compound is used to formthe catalyst, separate solutions of the metal compounds, in the same ordifferent solvents, can be prepared and then combined. If necessary, thesolutions may be aged, for example, at room temperature until anequilibrium condition is established therein prior to combining themetal solutions to form an impregnation solution.

The alumina carrier material is thereafter admixed with the impregnationsolution. The amount of the metal contained in this impregnationsolution can be in the range of about 0.3 to about 1.5 wt % on anelemental basis. In order to insure uniform dispersion of the metalliccomponents throughout the carrier material, the amount of the hydrogenchloride used in this impregnation solution is about 3 wt % of thealumina particles. This impregnation step is performed by adding thecarrier material particles to the impregnation mixture with constantagitation. In addition, the volume of the solution is approximately thesame as the void volume of the carrier material particles so that all ofthe particles are immersed in the impregnation solution. Theimpregnation mixture is maintained in contact with the carrier materialparticles for a period of about ½ to about 3 hours at a temperature ofabout 70° F. Thereafter, the temperature of the impregnation mixture israised to about 225° F. and the excess solution is evaporated in aperiod of about 1 hour. The resulting dried impregnated particles arethen subjected to an oxidation treatment in a dry air stream at atemperature of about 975° F. and a GHSV of about 500 hr⁻¹ for about ½hour. This oxidation step is designed to convert substantially all ofthe metallic ingredients to the corresponding oxide forms. The resultingoxidized spheres are subsequently contacted in a halogen treating stepwith an air stream containing H₂O and HCl in a mole ratio of about 30:1for about 2 hours at 975° F. and a GHSV of about 500 hr⁻¹ in order toadjust the halogen content of the catalyst particles to a value of about1.09 wt %. The halogen-treated spheres are thereafter subjected to asecond oxidation step with a dry air stream at 975° F. and a GHSV of 500hr⁻¹ for an additional period of about ½ hour. The oxidized andhalogen-treated catalyst particles may then be subjected to a drypre-reduction treatment, designed to reduce at least the platinumcomponent to the elemental state, by contacting them for about 1 hourwith a substantially hydrocarbon-free dry hydrogen stream containingless than 5 vol ppm H₂O at a temperature of about 1050° F., a pressureslightly above atmospheric, and a flow rate of the hydrogen streamthrough the catalyst particles corresponding to a GHSV of about 400hr⁻¹.

A sample of the resulting reduced catalyst particles is analyzed andwill be found to contain, on an elemental basis, about 0.30 to about 1.5wt. % desired metal, and about 1.09 wt. % chloride.

Example 2

In this example, the present invention, is illustrated as applied to thehydrogenation of aromatic hydrocarbons such as benzene, toluene, thevarious xylenes, naphthalenes, etc., to form the corresponding cyclicparaffins. The corresponding cyclic paraffins, resulting from thehydrogenation of the aromatic nuclei, include compounds such ascyclohexane, mono-, di-, tri-substituted cyclohexanes,decahydronaphthalene, tetrahydronaphthalene, etc., which find widespreaduse in a variety of commercial industries in the manufacture of nylon,as solvents for various fats, oils, waxes, etc.

Aromatic concentrates are obtained by a multiplicity of techniques. Forexample, a benzene-containing fraction may be subjected to distillationto provide a heart-cut which contains the benzene. This is thensubjected to a solvent extraction process which separates the benzenefrom the normal or iso-paraffinic components, and the naphthenescontained therein. Benzene is readily recovered from the selectedsolvent by way of distillation, and in a purity of 99.0% or more. Inaccordance with the present process, the benzene is hydrogenated incontact with a low acidity catalytic composite containing 0.01 to about12.0% by weight of a metal component, e.g. platinum component or amixture of metals, and from about 0.01 to about 1.5% by weight of analkalinous metal component. Operating conditions include a maximumcatalyst bed temperature in the range of about 200° to about 800° F., apressure of from 500 to about 2,500 psig, a liquid hourly space velocityof about 1.0 to about 10.0 and a hydrogen circulation rate in an amountsufficient to yield a mole ratio of hydrogen to cyclohexane, in theproduct effluent from the last reaction zone, not substantially lessthan about 4.0:1. Although not essential, one preferred operatingtechnique involves the use of three reaction zones, each of whichcontains approximately one-third of the total quantity of catalystemployed. The process is further facilitated when the total freshbenzene is added in three approximately equal portions, one each to theinlet of each of the three reaction zones.

The catalyst utilized is an alumina carrier material combined with about0.3 to about 1.5% by weight of metal, such as platinum, and about 0.90%by weight of lithium, all of which are calculated on the basis of theelemental metals. The hydrogenation process will be described inconnection with a commercially-scaled unit having a total fresh benzenefeed capacity of about 1,488 barrels per day. Make-up gas in an amountof about 741.6 mols/hr. together with hydrogen recovered from thereactor effluent is admixed with 2,396 Bbl/day (about 329 mols/hr) of acyclohexane recycle stream, the mixture being at a temperature of about137° F., and further mixed with 96.24 mols/hr (582 Bbl./day) of thebenzene feed; the final mixture constitutes the total charge to thefirst reaction zone. Following suitable heat-exchange with various hoteffluent streams, the total feed to the first reaction zone is at atemperature of 385° F. and a pressure of 460 psig. The reaction zoneeffluent is at a temperature of 606° F. and a pressure of about 450psig. The total effluent from the first reaction zone is utilized as aheat-exchange medium, in a stream generator, whereby the temperature isreduced to a level of about 545° F. The cooled effluent is admixed withabout 98.5 moles per hour (596 Bbl./day) of fresh benzene feed, at atemperature of 100° F.; the resulting temperature is 400° F., and themixture enters the second reaction zone at a pressure of about 440 psig.The second reaction zone effluent, at a pressure of 425 psig. and atemperature of 611° F., is admixed with 51.21 mols/hr (310 Bbl./day) offresh benzene feed, the resulting mixture being at a temperature of5788° F. Following its use as a heat-exchange medium, the temperature isreduced to 400° F., and the mixture enters the third reaction zone at apressure of 415 psig. The third reaction zone effluent is at atemperature of about 500° F. and a pressure of about 400 psig. Throughutilization as a heat-exchange medium, the temperature is reduced to alevel of about 244° F., and subsequently reduced to a level of about115° F. by use of an air-cooled condenser. The cooled third reactionzone effluent is introduced into a high pressure separator, at apressure of about 370 psig.

A hydrogen-rich vaporous phase is withdrawn from the high pressureseparator and recycled by way of compressive means, at a pressure ofabout 475 psig, to the inlet of the first reaction zone. A portion ofthe normally liquid phase is recycled to the first reaction zone as thecyclohexane concentrate hereinbefore described. The remainder of thenormally liquid phase is passed into a stabilizing column functioning atan operating pressure of about 250 psig, a top temperature of about 160°F. and a bottom temperature of about 430° F. The cyclohexane product iswithdrawn drawn from the stabilizer as a bottoms stream, the overheadstream being vented to fuel. The cyclohexane concentrate is recovered inan amount of about 245.80 moles per hour, of which only about 0.60 molesper hour constitutes other hexanes. In brief summation then, from the19,207 pounds per hour of fresh benzene feed, 20,685 per hour ofcyclohexane product is recovered.

Example 3

Another hydrocarbon hydroprocessing scheme, to which the presentinvention is applicable, involves the hydrorefining of coke-forminghydrocarbon distillates. The hydrocarbon distillates generally containmono-olefinic, di-olefinic and aromatic hydrocarbons. Through theutilization of a catalytic composite comprising a noble metal component,increased selectivity and stability of operation is obtained;selectivity is most noticeable with respect to the retention ofaromatics, and in hydrogenating conjugated diolefinic and mono-olefinichydrocarbons. Such charge stocks generally result from diverseconversion processes including the catalytic and/or thermal cracking ofpetroleum, sometimes referred to as pyrolysis, the destructivedistillation of wood or coal, shale oil retorting, etc. The impuritiesin these distillate fractions must necessarily be removed before thedistillates are suitable for their intended use, or which when removed,enhance the value of the distillate fraction for further processing.Frequently, it is intended that these charge stocks be saturated to theextent necessary to remove the conjugated di-olefins, whilesimultaneously retaining the aromatic hydrocarbons. When subjected tohydrorefining for the purpose of removing the contaminating influences,there is encountered difficulty in effecting the desired degree ofreaction due to the formation of coke and other carbonaceous material.

As utilized herein, “hydrogenating” is intended to be synonymous with“hydrorefining.” The purpose is to provide a highly selective and stableprocess for hydrogenating coke-forming hydrocarbon distillates, and thisis accomplished through the use of a fixed-bed catalytic reaction systemutilizing a metal catalyst component. There exists two separate,desirable routes for the treatment of coke-forming distillates, forexample a pyrolysis naphtha by-product. One such route is directedtoward a product suitable for use in certain gasoline blending. Withthis as the desired object, the process can be effected in a singlestage, or reaction zone, with the catalytic composite hereinafterspecifically described as the first-stage catalyst. The attainableselectivity in this instance resides primarily in the hydrogenation ofhighly reactive double bonds. In the case of conjugated di-olefins, theselectivity afforded restricts the hydrogenation to producemono-olefins, and, with respect to the styrenes, for example, thehydrogenation is inhibited to produce alkyl benzenes without “ring”saturation. The selectivity is accomplished with a minimum of polymerformation either to “gums,” or lower molecular weight polymers whichwould necessitate a re-running of the product before blending togasoline would be feasible. It must be noted that the mono-olefins,whether virgin, or products of di-olefin partial saturation, areunchanged in the single, or first-stage reaction zone. Where however thedesired end result is aromatic hydrocarbon retention, intended forsubsequent extraction, the two-stage route is required. The mono-olefinsmust be substantially saturated in the second stage to facilitatearomatic extraction by way of currently utilized methods. Thus, thedesired necessary hydrogenation involves saturation of the mono-olefins.Attendant upon this is the necessity to avoid even partial saturation ofaromatic nuclei.

With respect to one catalytic composite, its principal function involvesthe selective hydrogenation of conjugated diolefinic hydrocarbons tomono-olefinic hydrocarbons. The catalytic composite comprises analumina-containing refractory inorganic oxide, a noble metal component,such as platinum, and an alkali-metal component, the latter beingpreferably potassium and/or lithium. Through the utilization of aparticular sequence of processing steps, and the use of the foregoingdescribed catalyst composites, the formation of high molecular weightpolymers is inhibited to a degree which permits processing for anextended period of time. Briefly, this is accomplished by initiating thehydrorefining reactions at temperatures below about 500° F., at whichtemperatures the coke-forming reactions are not promoted.

The hydrocarbon distillate charge stock, for example a light naphthaby-product from a commercial cracking unit designed and operated for theproduction of ethylene, having a gravity of about 34.0° API, a brominenumber of about 35.0, a diene value of about 17.5 and containing 75.9vol. % aromatic hydrocarbons, is admixed with recycled hydrogen. Thislight naphtha co-product has an initial boiling point of about 164° F.and an end boiling point of about 333° F. The hydrogen circulation rateis within the range of from about 1,000 to about 10,000 scf/Bbl, andpreferably in the narrower range of from 1,500 to about 6,000 scf/Bbl.The charge stock is heated to a temperature such that the maximumcatalyst temperature is in the range of from about 200° F. to about 500°F., by way of heat-exchange with various product effluent streams, andis introduced into the first reaction zone at an LHSV in the range ofabout 0.5 to about 10.0. The reaction zone is maintained at a pressureof from 400 to about 1,000 psig, and preferably at a level in the rangeof from 500 to about 900 psig.

The temperature of the product effluent from the first reaction zone isincreased to a level above about 500° F., and preferably to result in amaximum catalyst temperature in the range of 600 to 900° F. Thesaturation of mono-olefins, contained within the first zone effluent, iseffected in the second zone. When the process is functioningefficiently, the diene value of the liquid charge entering the secondcatalyst reaction zone is less than about 10.0 and often less than about0.3. The second catalytic reaction zone is maintained under an imposedpressure of from about 400 to about 1,000 psig, and preferably at alevel of from about 500 to about 900 psig. The two-stage process isfacilitated when the focal point for pressure control is the highpressure separator serving to separate the product effluent from thesecond catalytic reaction zone. It will, therefore, be maintained at apressure slightly less than the first catalytic reaction zone, as aresult of fluid flow through the system. The LHSV through the secondreaction zone is about 0.5 to about 10.0, based upon fresh feed only.The hydrogen circulation rate will be in a range of from 1,000 to about10,000 scf./Bbl., and preferably from about 1,000 to about 8,000scf./Bbl. Series-flow through the entire system is facilitated when therecycle hydrogen is admixed with the fresh hydrocarbon charge stock.Make-up hydrogen, to supplant that consumed in the overall process, maybe introduced from any suitable external source, but is preferablyintroduced into the system by way of the effluent line from the firstcatalytic reaction zone to the second catalytic reaction zone.

With respect to the naptha boiling range portion of the producteffluent, the aromatic concentration is about 75.1% by volume, thebromine number is less than about 0.3 and the diene value is essentially“nil”.

With charge stocks having exceedingly high diene values, a recyclediluent is employed in order to prevent an excessive temperature rise inthe reaction system. Where so utilized, the source of the diluent ispreferably a portion of the normally liquid product effluent from thesecond catalytic reaction zone. The precise quantity of recycle materialvaries from feed stock to feed stock; however, the rate at any giventime is controlled by monitoring the diene value of the combined liquidfeed to the first reaction zone. As the diene value exceeds a level ofabout 25.0, the quantity of recycle is increased, thereby increasing thecombined liquid feed ratio; when the diene value approaches a level ofabout 20.0, or less, the quantity of recycle diluent may be lessened,thereby decreasing the combined liquid feed ratio.

Example 4

This illustration of a hydrocarbon hydroprocessing scheme, encompassedby our invention is one which involves hydrocracking heavyhydrocarbonaceous material into lower-boiling hydrocarbon products. Inthis instance, the preferred catalysts contain a germanium component, aplatinum group metal component, a cobalt component, and a halogencomponent combined with a crystalline aluminosilicate-carrier material,such as faujasite, and one which is at least 90.0% by weight zeolitic.

Most of the virgin stocks, intended for hydrocracking, are contaminatedby sulfurous compounds and nitrogenous compounds, and, in the case ofthe heavier charge stocks, various metallic contaminants, insolubleasphalts, etc. Contaminated charge stocks are generally hydrorefined inorder to prepare a charge suitable for hydrocracking. Thus, thecatalytic process of the present invention can be beneficially utilizedas the second stage of a two-stage process, in the first stage of whichthe fresh feed is hydrorefined.

Hydrocracking reactions are generally effected at elevated pressures inthe range of about 800 to 5,000 psig, and preferably at someintermediate level of 1,000 to about 3,500 psig. Liquid hourly spacevelocities of about 0.25 to about 10.0 will be suitable, the lower rangegenerally reserved for the heavier stocks. The hydrogen circulation ratewill be at least about 3,000 scf/Bbl, with an upper limit of about50,000 scf/Bbl, based upon fresh feed. For the majority of feed stocks,hydrogen circulation in the range of 5,000 to 20,000 scf./Bbl. willsuffice. With respect to the LHSV, it is based upon fresh feed,notwithstanding the use of recycle liquid providing a combined liquidfeed ratio in the range of about 1.25 to about 6.0. The operatingtemperature again alludes to the temperature of the catalyst within thereaction zone, and is in the range of about 400° to about 900° F. Sincethe principal reactions are exothermic in nature, the increasingtemperature gradient, experienced as the charge stock traverses thecatalyst bed, results in an outlet temperature higher than that at theinlet to the catalyst bed. The maximum catalyst temperature should notexceed 900° F., and it is generally a preferred technique to limit thetemperature increase to 100° F. or less.

Although amorphous composites of alumina and silica, containing fromabout 10.0 to about 90.0% by weight of the latter, are suitable for usein the catalytic composite employed in the present process, a preferredcarrier material constitutes a crystalline aluminosilicate, preferablyfaujasite, of which at least about 90.0% by weight is zeolitic. Thiscarrier material, and a method of preparing the same, have hereinbeforebeen described.

A specific illustration of this hydrocarbon hydroprocessing techniqueinvolves the use of a catalytic composite of about 0.4 to about 2.8% byweight of platinum, 0.7% by weight of combined chlorine, combined with acrystalline aluminosilicate material of which about 90.0% by weightconstitutes faujasite. This catalyst is intended for utilization in theconversion of 16,000 Bbl/day of a blend of light gas oils to producemaximum quantities of a heptane-400° F. gasoline boiling range fraction.The charge stock has a gravity of 33.8° API, and has an initial boilingpoint of 369° F., a 50% volumetric distillation temperature of 494° F.and an end boiling point of 655° F. The charge stock is initiallysubjected to a clean-up operation at maximum catalyst temperature of750° F., an LHSV of 1.0 with a hydrogen circulation rate of about 5000scf/Bbl The pressure imposed upon the catalyst within the reaction zoneis about 1,500 psig. Since at least a portion of the blended gas oilcharge stock will be converted into lower-boiling hydrocarbon products,the effluent from this clean-up reaction zone is separated to provide anormally liquid, 400° F.-plus charge for the hydrocracking reaction zonecontaining the hereinabove described catalyst. The pressure imposed uponthe second reaction zone is about 1,500 psig, and the hydrogencirculation rate is about 8,000 scf/Bbl The original quantity of freshfeed to the clean-up reaction zone is about 16,000 Bbl/day; followingseparation of the first zone effluent to provide the 400° F.-plus chargeto the second reaction zone, the charge to the second reaction zone isin an amount of about 12,150 Bbl/day, providing an LHSV of 0.85. Thetemperature at the inlet to the catalyst bed is 665° F., and aconventional hydrogen quench stream is utilized to maintain the maximumreactor outlet temperature at about 700° F. Following separation of theproduct effluent from the second reaction zone, to concentrate thedesired gasoline boiling range fraction, the remaining 400° F.-plusnormally liquid material, in an amount of 7,290 Bbl/day, is recycled tothe inlet of the second reaction zone, thus providing a combined liquidfeed ratio thereto of about 1.60.

An analysis of the components in stage 1 and stage 2 is carried out toassess the yields of ammonia, hydrogen sulfide, methane, ethane,propane, butanes, pentanes, hexanes, C7-400° F. and 400° F.-plusproducts. An analysis of the gravity values of the combinedpentane/hexane fraction is carried out. A gravity of 85.0 corresponds toa clear research octane rating and gravity of 99.0 corresponds to aleaded research octane rating for pentane/hexane. A sample in this rangeconstitutes an excellent blending component for motor fuel. The gravityof a desired heptane-400° F. product for a clear research octane ratingis 72.0 and a leaded research octane rating is 88.0.

While the disclosure includes a limited number of embodiments, thoseskilled in the art, having the benefit of this disclosure, willappreciate that other embodiments may be devised which do not departfrom the scope of the present disclosure.

What is claimed is:
 1. A process for selective ring-opening of aromaticand cycloparaffinic rings comprising: contacting hydrocarbon speciescomprising aromatic and cycloparaffinic rings with hydrogen in thepresence of a ring-opening catalyst comprising a noble metal on alow-acidity crystalline material comprising external pockets tofacilitate ring-opening of the hydrocarbon species comprising aromaticand cycloparaffinic rings.
 2. The process of claim 1, wherein theexternal pockets of the low-acidity crystalline material are formed bythe delamination of zeolites.
 3. The process of claim 1, wherein thelow-acidity crystalline material is formed from the delamination of oneor more types of zeolite selected from a borosilicate oraluminoborosilicate molecular sieve containing at least 0.05 weightpercent boron and less than 1000 ppm by weight of aluminum, or atitanosilicate molecular sieve; aluminosilicate; and silico-aluminiumphosphates and mixtures thereof.
 4. The process of claim 1, wherein thelow-acidity crystalline material is formed from the delamination of oneor more types of zeolite selected from SSZ-33, SSZ-46, SSZ-53, SSZ-55,SSZ-57, SSZ-58, SSZ-59, SSZ-60, SSZ-64, SSZ-70, ZSM-5, ZSM-11, TS-1, MTT(e.g., SSZ-32, ZSM-23 and the like), H—Y and combinations thereof. 5.The process of claim 1, wherein the low-acidity crystalline material isformed from the delamination of one or more types of aluminosilicatezeolite.
 6. The process of claim 1, wherein the noble metal is selectedfrom the group consisting of platinum, palladium, nickel, rhodium,iridium, ruthernium, osmium and mixtures thereof.
 7. The process ofclaim 1, wherein the process is carried out at a temperature of about200° C. to about 400° C., a pressure in the range of about 200 psig toabout 2000 psig, and weight hourly space velocity in the range of about0.4 to about 0.7 WHSV hr⁻¹.
 8. A process for converting polynucleararomatic hydrocarbons (PAHs) to ring-opened products comprising: (i)hydrogenation of PAHs by a hydrogenation catalyst and hydrogen toproduce hydrocarbon species comprising aromatic and cycloparaffinicrings; and (ii) contacting the hydrocarbon species comprising aromaticand cycloparaffinic rings with hydrogen in the presence of aring-opening catalyst comprising a noble metal on a low-aciditycrystalline material comprising external pockets to facilitatering-opening of the hydrocarbon species comprising aromatic andcycloparaffinic rings.
 9. The process of claim 8, wherein the PAHscomprise C₁₀ to C₃₂ PAHs.
 10. The process of claim 8, wherein the PAHsare from a hydrocracker recycle stream.
 11. The process of claim 8,wherein the external pockets of the low-acidity crystalline material areformed by the delamination of zeolites.
 12. The process of claim 8,wherein the low-acidity crystalline material is formed from thedelamination of one or more types of zeolite selected from aborosilicate or aluminoborosilicate molecular sieve containing at least0.05 weight percent boron and less than 1000 ppm by weight of aluminum,or a titanosilicate molecular sieve; aluminosilicate; andsilico-aluminium phosphates and mixtures thereof.
 13. The process ofclaim 8, wherein the low-acidity crystalline material is formed from thedelamination of one or more types of zeolite selected from SSZ-33,SSZ-46, SSZ-53, SSZ-55, SSZ-57, SSZ-58, SSZ-59, SSZ-60, SSZ-64, SSZ-70,ZSM-5, ZSM-11, TS-1, MTT (e.g., SSZ-32, ZSM-23 and the like), H—Y andcombinations thereof.
 14. The process of claim 8, wherein thelow-acidity crystalline material is formed from the delamination of oneor more types of aluminosilicate zeolite.
 15. The process of claim 8,wherein the noble metal is selected from the group consisting ofplatinum, palladium, nickel, rhodium, iridium, ruthernium, osmium andmixtures thereof.
 16. The process of claim 8, wherein the process iscarried out at a temperature of about 200° C. to about 400° C., apressure in the range of about 200 psig to about 2000 psig, and weighthourly space velocity in the range of about 0.4 to about 0.7 WHSV hr⁻¹.17. A composition comprising a ring-opened hydrocarbon species producedfrom hydrocarbon species comprising aromatic and cycloparaffinic ringstreated in accordance with the process of claim
 1. 18. A compositioncomprising a ring-opened hydrocarbon species produced from hydrocarbonspecies comprising aromatic and cycloparaffinic rings treated inaccordance with the process of claim 8.